1. Field of the Invention
The present invention relates to an apparatus for electrically connecting electronic units together, and in particular, to an apparatus for electrically connecting electronic units together via a connector supported by a supporting member such as a circuit board.
2. Description of the Prior Art
In the following description, an electronic circuit package or an electronic unit means a plurality of electronic parts integrated together. The electronic circuit package or electronic unit includes, for example, a circuit board on which an LSI is mounted, a circuit board on which a connector is mounted, a hard disk unit, and a CPU package.
In the following description, a connector means a device that electrically connects electronic parts. Either a portion having a female terminal or a portion having a male terminal is a connector. Accordingly, a group of terminals provided at an edge of a circuit board is also a connector as in the case of a terminal 65 in FIG. 7.
In the following description, a housing means a device that accommodates or supports electronic units. For example, a case, a cabinet, a rack, a chassis, and a frame are housings.
In a first conventional technique for an apparatus of this kind, a back board 72 has a connector 73, and a plurality of electronic circuit packages 71 are connected to the back board 72 via a connector 74, as shown in FIG. 9. Each of the electronic circuit packages 71 has a circuit board and electronic parts such as LSIs 75 which are mounted on the circuit board. A wiring pattern 77 of the electronic circuit package 71 connects the electronic parts such as the LSIs 75 and the connector 74 together. The connector 74 is connected to a connector 73 to electrically connect the electronic circuit package 71 to another electronic circuit package via a wiring pattern 76 in the back board 72.
In this structure, as shown in FIG. 10, an electronic circuit package 81 is inserted into a connector 82 in its longitudinal direction, that is, perpendicularly to the direction in which terminals 83 of the connector 82 are arranged so that a terminal of the electronic circuit package 81 is connected to the terminal 83 of the connector 82.
Japanese Patent Laid-Open No. 09-172240 discloses a variation of the above first conventional technique. In this variation, packages are connected to the respective surfaces of the back board. Specifically, FIG. 1 of Japanese Patent Laid-Open No. 09-172240 shows a device that electrically connects a group of first packages composed of 16 first packages to a group of second packages composed of 16 second packages, via an adapter 30 having 16 connectors 33 arranged on each of its front and back surfaces. The adapter 30 and the connector 33 correspond to the back board 72 and connector 73, shown in FIG. 9 of this application.
If the apparatus according to the first conventional technique shown in FIG. 9 is mounted in a housing, it is arranged so that the back board 72 is substantially perpendicular to the top or bottom surface of the housing. Then, the electronic circuit package 71 is inserted into the housing through an opening formed in the front surface of the housing. Subsequently, the connector 74 of the electronic circuit package 71 is connected to the connector 73 of the back board 72.
U.S. Pat. No. 6,128,196 discloses a second conventional technique for an apparatus for electrically connecting electronic units together. With reference to FIGS. 2 and 9 of U.S. Pat. No. 6,128,196, a circuit board 102 is inserted into a connector 152 of a motherboard 149 from a direction perpendicular to the longitudinal direction of the connector 152. The motherboard 149 is arranged in a chassis 104 so that the motherboard 149 is parallel to the top surface (or bottom surface) of the chassis 104.
However, the above first conventional technique has the following problems.
A first problem is a decrease in cooling efficiency. If a cooling airflow- is allowed to flow parallel to the inserting direction of the electronic circuit package 71, the back board 72 interrupts the airflow. If the size of the back board is reduced to allow the airflow to flow without being interrupted by the back board 72, the size of the connector is also reduced. This in turn reduces the number of signal lines and an amount of a current supply. On the other hand, if the cooling airflow is allowed to flow in a direction parallel to the back board 72, that is, in the vertical direction of FIG. 9, no other devices can be mounted above or below this electronic equipment.
With the second conventional technique, the motherboard 149 is arranged in the chassis 104 so as to be parallel to the top surface (or bottom surface) of the chassis 104. Accordingly, the cooling airflow is parallel to the motherboard 149. Thus, the second conventional technique can solve the above problems of the first conventional technique. However, with the second conventional technique, the circuit board 102 is moved up and down to connect and separate the circuit board 102 to and from the motherboard connector 152, respectively. Thus, it is difficult to connect and separate the circuit board 102 to and from the motherboard connector 152 unless there is a sufficient clearance between the circuit board 102 and the top surface 124 of the chassis 104. This problem is particularly severe when the size of the chassis 104 is reduced.
According to U.S. Pat. No. 6,128,196, a 1⅜-inch clearance is required on an average to connect and separate the circuit board connector 102 to and from the motherboard connector 152. With reference to FIG. 3 of U.S. Pat. No. 6,128,196, the circuit board 102 is accommodated in a framework 159. The framework 159 has a pivot 210. The circuit board 102 can be moved up or down by 1⅜ inches or more by engaging the pivot 210 with a receiving block 220.
However, since the size of the chassis 104 is reduced, it is difficult to connect and separate the circuit board 102 to and from the motherboard 149 when the clearance between the circuit board 102 and the top surface 124 of the chassis 104 is less than 1⅜ inches.